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Industrial Prospect of ……..,Bellamya bengalensis Review of Literature 3. REVIEW OF LITERATURE 3.1 Importance of Molluscs Aquatic ecosystem provides a home to various kinds of biota, including phytoplanktons, zooplanktons, aquatic plants, insects, molluscs etc. They are organized at many levels from smallest building blocks of life to complete ecosystems, encompassing communities, populations, species and genetic levels. The representatives of phylum Arthropoda and Mollusca generally colonize all aquatic ecosystems around the globe. The meaning of “Mollusca” is "Soft bodied animal", (from the Latin word “Mollis”, the word mollusca was derived, which means “Soft”). On the other hand, by the way, the field of biology dealing with molluscs is called “Malacology”. From the Greek word “Malakos”, the word malacology was derived, it bears the meaning also soft (Nordsieck, 2012). Mollusca, the second largest metazoan taxon after arthropoda. Mollucscs consist of Aplacophora, Polyplacophora, Monoplacophora, Gastropoda, Cephalopoda, Bivalvia, and Scaphopoda. There are about 55,400 numbers (no.) of molluscan community were reported to be available in this world. Among these molluscan community “Gastropods” confirm their lion share (43,000 no.), followed by “Bivalvia” (10,000 no.), “Cephalopoda” (650 no.) and others groups (Nordsieck, 2012). According to the archaeological findings, molluscs have been used since the dawn of humankind. Mussels and later snails were collected for eating, as well as for the fabrication of different types of furniture and household items. Today regarding their commercial significance, people are thinking about their sustainable development at the farms in several parts of the world. Even today, certain ethnic groups use sea shells as ceremonial trumpets (Nordsieck, 2012). However in West Bengal, Bellamya bengalensis Chakraborty,. D.,2015 Ph.D. thesis 10 Industrial Prospect of ……..,Bellamya bengalensis Review of Literature regarded as dominating fresh water gastropod (according to demand and economical importance) followed by Lamellidence spp. (bivalbia). 3.2 Taxonomical and biological features of Bellamya bengalensis and its allied Genera Mollusca is the dominant group of animal among the benthic inhabitant. Benthic invertebrates occupy the bottom of water body. The functional role of benthic communities in the trophic dynamics of aquatic ecosystem is well acknowledged. The composition, distribution of these benthic organisms over a period of time provide index of the ecosystem (Pir et.al.,2010). Regarding taxonomical and distributional work of this fresh water snail Choubisa (1992) collected 32 species of molluscs from various freshwater habitats of southern Rajasthan. Where as Clarke (1979) attempted to show the utility of molluscs in primary classification of the rivers in their various trophic stages. 3.2.1 Systematic Position Kingdom: Animalia Phylum: Mollusca Subphylum: Conchifera Class: Gastropoda Subclass: Prosobranchiata Order: Caenogastropoda Suborder: Mesogastropoda Family: Viviparidae Subfamily: Bellamyinae Genus: Bellamya Species: B. bengalensis (Lamarck) 3.2.2 Synonyms Vivipara bengalensis Preston (1915), Filopaludina (Filopaludina) bengalensis (whilst Nesemann et al. 2007). Chakraborty,. D.,2015 Ph.D. thesis 11 Industrial Prospect of ……..,Bellamya bengalensis Review of Literature 3.2.2.1 Taxonomic Note Brandt (1974) treated Bellamya bengalensis as Filopaludina (Filopaludina) bengalensis while Nesemann et.al. (2007) treat B. bengalensis as Bellamya (Filopaludina) bengalensis (Lamarck, 1822). Based on the shell characteristics 22 forms have been recognized by Annandale (1921), including B. bengalensis f. balteata, B. bengalensis f.typica, B. bengalensis f. annandalei, B. bengalensis f. mandiensis, B. bengalensis f.colairensis, B. bengalensis f. doliaris, B. bengalensis f. nepalensis and B. bengalensis f.eburnea etc. 3.2.3 Geographical Distribution Bellamya bengalensis is a hardy, common freshwater mollusc which is widely distributed in south-east Asia. Found in both lentic and lotic habitat. It is found in both lentic and lotic habitats in India (Andaman and Nicobar Islands, Andhra Pradesh, Arunachal Pradesh, Assam, Bihar, Chandigarh, Dadra-Nagar-Haveli, Daman and Diu, Delhi, Goa, Gujarat, Haryana, Himachal Pradesh, Jammu-Kashmir, Jharkhand, Karnataka, Kerala, Madhya Pradesh, Maharashtra, Mahe, Manipur, Meghalaya, Mizoram, Nagaland, Odissa, Pondicherry, Punjab, Rajasthan, Sikkim, Tamil Nadu, Tripura, Uttaranchal, Uttar Pradesh, West Bengal), Bangladesh, Iran, Islamic Republic of Myanmar, Nepal, Pakistan, Sri Lanka etc (Ali and Chakraborty,1992; Budha, et.al. 2010; Saha et. al., 2013). 3.2.4 Population Population size and trends of this species is not well known. However, it is a common and abundant species found in high numbers in all kinds of freshwater bodies (Budha, et.al. 2010). Chakraborty,. D.,2015 Ph.D. thesis 12 Industrial Prospect of ……..,Bellamya bengalensis Review of Literature 3.2.5 Habitat and Ecology This species is present, in almost all types of lowland water bodies, mainly stagnant water and low saline water resources such as rivers, streams, lakes, ponds, wetlands, marshes, ditches, paddy fields, etc. It can tolerate a maximum level of salinity of 0.2 mg/l (Ramakrishna and Dey, 2007, Budha et.al.2010, Saha et.al., 2013). 3.2.6 Diagnostic characters The shell of B. bengalensis is more or less oval in shape and acuminate which consist of calcareous shell. The upper part of the shell is slightly conidial. The body whorl is evenly convex in pro-file. The aperture is sub-circular and has a narrow black margin. It is slightly oblique. The umbilicus is narrow (Saha et.al., 2013). Beside these typical characters of the molluscs, it consists head with mouth and sense organs, eye, one gill, one nephrdium, and one atrium are present. A visceral mass containing gut, heart, gonads, kidney, tentacles, a ventral muscular foot, a shell mantle and radula. B. bengalensis has operculum, this operculum is moderately thin, deep brownish complexion with teardrop-shaped disk of flexible protein that forms a door close like aperture. The external surface of operculum is convex, the outer margin is strongly curved, the inner margin is slightly sinuate and the posterior margin bluntly pointed. It has two long cephalic tentacles which are located dorsally beside the base of the snout (Ghobadi. and Farahnak., 2004). The colouration varies considerably but it is never brilliant (Saha et.al., 2013). The ground colour is greenish gray and opaque. The brown dark bands are variable and irregular. As this snail is viviparous, the females release fully developed small snails, hence it is commonly called as "live-bearing snail" Chakraborty,. D.,2015 Ph.D. thesis 13 Industrial Prospect of ……..,Bellamya bengalensis Review of Literature 3.2.7 Use and trade Bellamya bengalensis is commonly used as food in Nepal, Bangladesh. In India it was observed for commonly use in Bihar, Jharkhand, Meghalaya, Odisha and West Bengal (Baby et al. 2010; Mahata, 2012, Chakraborty et al. 2014). 3.2.8 Assessment Information Bellamya bengalensis is very common species for selling and edible purpose and it also poses ethno medicinal values mainly to the rural people. This fresh water snail carries indispensible nutrients in very cheap rate in term of money than other edible animal sources (fish, meat, egg etc) (Mukherjee and Basu,2008). This species is harvested from the different kinds of water bodies. At current levels, this species is assessed as “Least Concern” as per IUCN categories red list categories Ver. 3.1 (Budha, et.al.2010). 3.2.9 Characteristic features of other Bellamya Genera The typical characteristic features of these viviparous snails that, they are not amphibious in nature, do not have lung, do not respire in air, and do not lay eggs. There are several types of Bellamya (Vivipera) species and they are differ from each other by their shell structures, shape of the apex, colour pattern etc. However, in some times identification becomes difficult due to unclear and contradicting descriptions in the literatures (Falkner 1989; Falniowski et. al. 1998; Glöer 2002).There are various other more or less similar species of Viviparus and related genera, especially, southeastern Europe and Asia. Shells of Bellamya (Cipangopaludina) chinensis and B. (C.) japonica (Asian viviparid species introduced in North America) are somewhat similar, especially B. japonica has acute apex, but differ, among others, by their unbranded shells and Chakraborty,. D.,2015 Ph.D. thesis 14 Industrial Prospect of ……..,Bellamya bengalensis Review of Literature different of the first whorls (Khan and Chaudhuri,1984). Beside Bellamya bengalensis there are another species Bellamya crassa which is made of strong sub-globe shell and it is riverine form which occurs in river with sandy bed, at lower part of this state. This species observed only in the Churni river at Nadia, West Bengal (Thakur and Mitra. 1992). But as per the 1996, IUCN Red List B. crassa was declared as threatened specimen (Nesemann et. al. 2007). 3.3 Ecological Importance of Bellamya bengalensis Bellamya bengalensis have great significance role in aquatic ecology. Because they form the food of fishes and their productivity play an important link in the food chain. Bellamya bengalensis are mainly filter feeder and detritivore, that’s why they can able to form an important link in the food chain. On account of their ability to convert low quality and low energy detritus into better quality
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  • Echinostoma Mekongi: Discovery of Its Metacercarial Stage in Snails, Filopaludina Martensi Cambodjensis, in Pursat Province, Cambodia

    Echinostoma Mekongi: Discovery of Its Metacercarial Stage in Snails, Filopaludina Martensi Cambodjensis, in Pursat Province, Cambodia

    ISSN (Print) 0023-4001 ISSN (Online) 1738-0006 Korean J Parasitol Vol. 59, No. 1: 47-53, February 2021 ▣ ORIGINAL ARTICLE https://doi.org/10.3347/kjp.2021.59.1.47 Echinostoma mekongi: Discovery of Its Metacercarial Stage in Snails, Filopaludina martensi cambodjensis, in Pursat Province, Cambodia 1,2, 3, 1 1 1 1 Jong-Yil Chai * , Woon-Mok Sohn * , Jaeeun Cho , Bong-Kwang Jung , Taehee Chang , Keon Hoon Lee , Virak Khieu4, Rekol Huy4 1Institute of Parasitic Diseases, Korea Association of Health Promotion, Seoul 07649, Korea; 2Department of Tropical Medicine and Parasitology, Seoul National University College of Medicine, Seoul 03080, Korea; 3Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju 52727, Korea; 4National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia Abstract: Echinostoma mekongi was reported as a new species in 2020 based on specimens collected from humans in Kratie and Takeo Province, Cambodia. In the present study, its metacercarial stage has been discovered in Filopaludina martensi cambodjensis snails purchased from a local market nearby the Tonle Sap Lake, Pursat Province, Cambodia. The metacercariae were fed orally to an experimental hamster, and adult flukes were recovered at day 20 post-infection. They were morphologically examined using light and scanning electron microscopes and molecularly analyzed by sequencing of their mitochondrial cox1 and nad1 genes. A total of 115 metacercariae (1-8 per snail) were detected in 60 (60.0%) out of 100 Filopaludina snails examined. The metacercariae were round, 174 µm in average diameter (163-190 µm in range), having a thin cyst wall, a head collar armed with 37 collar spines, and characteristic excretory granules.